1. Field of the Invention
The present invention relates to a turret punch press comprising rotatable upper and lower turrets which support a plurality of exchangeable punches and dies, and, in particular, to a turret punch press which is provided with a striker movable in two directions in a horizontal plane, for striking the indexed punches and dies, and wherein, once the indexed position of the upper and lower turrets for the processing region has been set, indexings of many punches and dies are done at the same time.
2. Description of the Prior Art
As is commonly known, a turret punch press is provided with a pair of fan- or disc-shaped rotatable upper and lower turrets which face each other in the vertical direction. On the upper and lower turrets, a plurality of punches and dies are provided for performing punching process. In addition, the turret punch press is provided with a ram which is movable in the vertical direction, and on which is mounted a striker for striking the punch which has been indexed (i.e. positioned) in the processing region by the rotation of the turrets. Further, the turret punch press is provided with a workpiece positioning device for positioning a workpiece in the processing region on a worktable, whereby a plate-shaped workpiece is moved in the X- and Y-axis directions.
Generally, in the turret punch press, after necessary punches and dies are indexed in the processing region by the rotation of the upper and lower turrets, the workpiece is positioned by the workpiece positioning device. Next, the punching process is performed on the workpiece by the ram striking the punch.
However, in the conventional turret punch press, because a simple punch and a single die can be indexed at the same time in the processing region by the rotation of the upper and lower turrets, after the punching process is carried out by the punch and die, the necessary indexing of the punch and the die must once again take place before the next punching process is performed by another punches and dies. In the turret punch press, the upper and lower turrets are comparatively heavy so that it is very difficult to quickly accomplish the indexing of the punch and die. Accordingly, the indexing of the punch and die with respect to the processing region must be performed at frequent intervals and considerable time is required. This is very inefficient.
A turret punch press disclosed in U.S. Pat. No. 3,685,380 is an example of a turret punch press in which processing can be performed relatively quickly by a plurality of punches and dies, once the indexing of the upper and lower turrets with respect to the processing region has been done.
In the turret punch press, however, a plurality of punches and dies are arranged in the radial direction of the upper and lower turrets. A striker mounted on the ram is constructed to be movable reciprocally in the radial direction of the turrets to cope with the radial arrangement of the punches and dies. Namely, in the prior arts, the punches and dies are arranged linearly, and the direction of the movement of the striker is also unidimensional. Accordingly, even when the punching process can be carried out by the plurality of punch and die pairs which are indexed with respect to the processing region by one rotation of the upper and lower turrets, no more than about three types of punch and die pairs can be used. Further, the punches and dies are restricted to small diameter tools.
In another conventional turret punch press, punches and dies are arranged uniformly on the circumference of a circle on the turret thereof, and the striker is mounted on the ram so as to be movable above the punches and the dies which are indexed with respect to the processing region.
In this type of configuration, it appears on first glance that the punches and dies are arranged two dimensionally, but if examined in the direction of the movement of the striker, it is seen that the striker can only move unidimensionally on the circumference of a circle, and the punches and dies are arranged unidimensionally on the circumference of the circle. Therefore, the arrangement of the punches and dies cannot be considered as a two-dimentional arrangement and is obviously a unidimensional arrangement.
At any rate, in a conventional turret punch press, no more than about three punch and die pairs can be used with a single rotational indexing of the upper and lower turrets relative to the processing region. Further the punches and dies are restricted to small diameter tools. Accordingly, improving in the processing efficiency is a problem.